The objectives of this study are a) to further characterize substrate transport systems in human normal and leukemia lymphocytes and granulocytes b) to further examine the responses of these systems to hormones in vitro and in vivo and c) to correlate hormone sensitivity with therapeutic responsitivity when hormone treatment is justified clinically. Initially, characterization of aminoacid and sugar transport as to rate of active and passive accumulation in individuals with leukemia, and correlation of velocity of aminoacid and sugar uptake with extent and rate of progression of disease will be made. Kinetic parameters of transport in leukemia and normal lymphocytes and leukemia myeloblasts will be examined. The effects of glycocorticoids and other hormones will be studied in order to examine their effect on the plasma membrane function of transport of low molecular weight nutrients. The sensitivity of aminoacid and sugar transport to hormones and the molecular specificity of steroid action will be examined by studying a) the effect of steroids of different molecular configuration, b) competitive effects of steroids and c) dependence on protein and RNA synthesis for steroid action. Studies of leukemia lymphocytes have revealed a reproducible and characteristic a) capacity for aminoacid transport in individual cell population and b) degree of sensitivity to cortisol inhibition. Moreover, leukemia myeloblasts have a much higher rate of aminoacid accumulation than leukemia lymphocytes and the former respond in vitro to cortisol treatment with an increase in aminoacid transport. We plan to extend these findings in order a) to enhance understanding of the nature of aminoacid and sugar transport and its hormonal regulation in leukemia leukocytes and the factors which contribute to variations in the metabolism of leukemia cell populations, b) to develop a method for predicting the effectiveness of hormone treatment and c) to uncover new modes of hormonal and non-hormonal treatments.